This disclosure describes a preventative breach detection system that detects and addresses potential resource breaches in candidate code-based infrastructure templates before deployment in a production environment within a cloud computing system. For example, the preventative breach detection system provides a preemptive security framework that utilizes hybrid pattern-based data structures, security pattern analysis, and resource vulnerability patterns to determine the security posture of a candidate code-based infrastructure based on its potential impact on the surrounding infrastructure in the production environment. By doing so, the preventative breach detection system quickly detects potential new resource breaches or changes in the security threat levels that may occur before the candidate code-based infrastructure is introduced into the production environment of the cloud computing system.